How to tell if motherboard is definitely faulty?

[steviewonder87]

So I just bought a 2nd hand Asrock H81M-ITX motherboard, and a 2nd hand 4790k to go along with it. The previous owner was using a Pentium G3258 and claims the board worked fine before selling it to me. I am pretty sure the CPU works fine and am working under that assumption.

I installed the new mobo and CPU and when I powered on my PC I got no signal at all and my PC just kept restarting every couple of seconds, sometimes staying on for less than a second, sometimes staying on for a few seconds, but no signal was ever given to the monitor.

I replaced the new mobo and CPU with my old mobo and CPU again and everything was fine, so this rules out any issue with the RAM, PSU, GPU, etc. I would assume (and yes I double checked everything was seated correctly in the new mobo, no loose ram sticks or whatever).

I did a bit of research (this is my first time changing a motherboard) and read that resetting the CMOS might resolve this issue, so (as described in the manual) I tried that; I held the power button until my PC turned off, unplugged the power cable, then held down the power button for a few seconds and then placed the jumper cap over pins 2 and 3 (as shown here - https://i.gyazo.com/1408d1ab14e4e000cf48aef754f23eb8.png) for 5 seconds, then placed the jumper cap back on pins 1 and 2, and reconnected my power cable and tried to turn on my PC once again (note that during this I had the motherboard outside the case and sitting on a cardboard box).

This time there was no power at all (I have the PSU connected to an LED strip in my case and not even that turned on) and after several attempts of unplugging the power and reconnecting the front panel power connector to no avail I gave up and put back my old mobo/CPU (at this point I wondered if I had broken my PSU somehow) but again, everything was fine and that's where I am now.

Is this motherboard just completely FUBAR? Is there anything else I should try (I'm honestly terrified of messing with it as I fear it's going to break my PSU or something else at this point) and is there any way to confirm that this motherboard is unusable, or is there a chance it's actually fine and I'm overlooking something simple?

Thanks in advance.

 

[Supahos]

Most likely the bios needs to be updated which will require a haswell (not haswell refresh/devil's canyon) chip.to do. You need a z or h97 to natively support your 4790k

 

[Supahos]

That cheap 3258 he had would do the trick or any other original haswell Pentium/Celeron

 

[steviewonder87]

Is there not a way of updating the BIOS without going out and buying another CPU?

 

[Supahos]

Other than borrowing a haswell cpu, or going to a brick and mortar computer shop no.

Well you could always buy a 9 series board instead

 

[steviewonder87]

What's the cheapest possible CPU model that would work? Would a G1820 do the trick?

 

[Supahos]

It should

 

[steviewonder87]

What's odd is that according to this http://www.cpu-upgrade.com/mb-ASRock/H81M-ITX.html both the G3258 and 4790k are supported from the same BIOS update (P1.70)? So shouldn't that mean if one works the other should too? And buying a G3258, or indeed any CPU not supported by 'any' BIOS update would be useless now? I assume since I reset the CMOS it's on the factory BIOS right now?

 

[Supahos]

Resetting the cmos just reverts all bios settings to stock, not typically reverting to factory bios as it gets replaced when new bios is flashed

If that was for sure the cpu he was using then yes it should have w bios supporting your 4790k unless he just got lucky and it ran on an older bios (sometimes it can work if it similar enough to previous ones)

 

[steviewonder87]

Thanks for the quick response. That is for sure the CPU he was using, which makes me wonder if the motherboard is actually faulty as I initially suspected. Is there any way of definitively knowing that?

Since there is no way to see what BIOS it has currently, it seems a bit of a risk buying another CPU that may not be supported either (not many cheap ones are supported by any BIOS apparently - odd since the majority are stock Haswell - especially ones available to me). Not really sure what to do now other than try sell this board and get another that definitely supports a 4790k out the box. I would have got a z97 but finding an ITX one is nigh on impossible unfortunately.

 

[Supahos]

Z97 and h97 are both options for certain compatibly.

I think it's probably the board as well. Also look at the socket. If any pins are bent the slightest it won't work. Or if there's any thermal paste in the socket

 

[steviewonder87]

The pins on both the CPU and socket appear to be fine, I think I can safely rule out that as the cause. And no paste anywhere it shouldn't be. It's a shame this board has no speaker so I can't diagnose that way either. I cannot find a single z97 or h97 (or even 87) in ITX size where I am, so think my only option is to get another h81 board. There's an ASUS one I've found that apparently should support a 4790k off the bat so guess I'll have to go for that. If that doesn't work then I guess it's the CPU that's borked in which case I'm really screwed...

 

[Supahos]

Any of those speakers should work I think that header is standard amongst boards

 

[steviewonder87]

Yeah I meant the board doesn't have a header at all, so I can't connect a speaker.

 

[steviewonder87]

OK so turned out the mobo does actually work!

Not sure what the deal was, but I took out the battery and replaced it and also removed a RAM stick (I know both sticks work because I've been using them for ages in my old rig, possibly it's the DIMM slot that's not working or possibly it was nothing to do with the RAM at all). At first it turned on for a second and turned off again, then turned on again and I actually got a signal, telling me the CPU and BIOS version (it was updated after all).

However I now have a new issue, in order to progress further I need my mouse and keyboard to work, and they don't. I tried multiple USB ports (they are wireless so I'm guessing it's missing the drivers for them?) and no dice. How can I get the computer to accept input from them before booting into Windows?

 

[Supahos]

Go buy a dirt cheap USB wired mouse and keyboard

https://pcpartpicker.com/product/w7Lypg/logitech-keyboard-920002565

Something like that, or surely someone you know has a mouse and keyboard with a wire you can use for a couple of hours

 

[steviewonder87]

So I confirmed that the reason the motherboard wouldn't POST before was having a RAM stick in the 2nd slot, it booted fine with just one stick (in either slot) but if I add 2 sticks it doesn't POST at all. Since both RAM sticks definitely work (I am using them right now on my old mobo) and both DIMM slots work, I'm guessing this isn't a hardware issue per se? Any ideas? I've read that this can be caused by having the CPU cooler too tight or uneven, it could possibly be that I suppose, the annoying thing is I have to remove it every time to access the RAM. I'll try with both sticks in and having the cooler a bit looser and see if that works.